W3school是一个很好的自学网站

'''
    爬取中国每个省份的大学名称和官网地址
'''

import requests
from lxml import etree


class School(object):
    def __init__(self):
        self.headers = {
            "User-Agent": "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/76.0.3809.100 Safari/537.36"
        }
        self.url = 'http://www.cnxiaoyuan.com/'

    # 省份学校
    def province_school_url(self):
        province = list()
        response = requests.get(url=self.url, headers=self.headers)
        html = etree.HTML(response.content.decode('utf-8'))

        # 省份学校url
        li_list = html.xpath("//div[@id='homecate']/ul/li")[0:-3]
        for li in li_list:
            province_school_url = li.xpath("./a/@href")
            for province_school in province_school_url:
                province_school = 'http://www.cnxiaoyuan.com/' + province_school
                province.append(province_school)
        return province

    # 获取每个省份的学校的url
    def school_url(self, province):
        school_list = list()
        for school in province:
            response = requests.get(url=school, headers=self.headers)
            html = etree.HTML(response.content.decode('utf-8'))

            # 每个省份的学校title和url
            li_list = html.xpath("//ul[@class='sitelist']/li")
            for li in li_list:
                school_title = li.xpath("./div/h3/a/text()")
                school_url = li.xpath("./div/address/a/text()")
                school_list.append(school_url)
                school_list.append(school_title)
                print(school_title, school_url)


if __name__ == '__main__':
    s = School()
    province = s.province_school_url()
    i = 0
    while i < 21:
        s.school_url(province)
        i += 1